The invention relates generally to containers and components thereof, and specifically to apparatus and methods for engaging and disengaging various members of a container or similar apparatus to each other. Although the invention is primarily illustrated in connection with various components of a collapsible container, it has a wide range of potential applications and uses other than for containers.
Prior art bulk containers (especially those that are injection molded or blow-molded or otherwise formed from plastic) sometimes include an option of having one or more sidewalls that either (1) are solid, or (2) include multiple parts moveable with respect to each other. An example of the latter is a sidewall with a fold down access door (or “drop door”). The access door typically is hinged in an opening in the sidewall and can be secured in alignment with the sidewall (by latches or some other interlock).
Prior art bulk containers are sometimes provided in “collapsible” embodiments, so that the sidewalls can be folded down onto the base (or the container can otherwise be flattened), to take up less space when the container is not in use. For such collapsible containers, latches are sometimes used to engage sidewalls with other sidewalls, to help hold those sidewalls in a desired container configuration.
Examples of such containers and drop doors are described in pending U.S. patent application Ser. No. 10/256,631 ('631), filed Sep. 27, 2002. The contents of that '631 application are hereby incorporated by reference to, among other things, provide context and background for the present invention.
Prior to the present invention, container manufacturers who wanted to provide customers with a selection of sidewalls (ones with drop-doors as well as ones without) not only had to manufacture both types of sidewalls, but had to maintain an inventory of both types, sell both types, service and repair both types, etc.
In addition, the latches used in many prior art containers are susceptible to improper insertion or orientation within the sidewall and/or drop door panel. If a latch is inserted “backwards” or otherwise improperly, it may not sufficiently or securely engage the two adjacent parts, risking damage to the container, or to people and/or property around or in the container.
Moreover, many of the latches on a single container typically are different from each other, and must be positioned in a specific location on the container in order to work properly. This is even more true for drop door models, in which latches to engage the drop door to the sidewall are typically different from the latches used to engage the sidewalls to each other and/or to the rest of the container. This results in potential confusion, lost assembly time, and mistakes in assembly (drop door latches may be inserted into sidewall latch positions) both during manufacture and maintenance. It also requires that manufacturers and users (for manufacture, maintenance, and replacement purposes) carry a relatively complex and extensive inventory of latches and related parts.
Prior art latches typically do not provide an optimum balance between (a) ruggedness and security once assembled within the container, and (b) ease of assembly/replacement/maintenance as the need may arise. Among other approaches, prior art designs include interfering tabs behind which the latches must be forced during insertion. The tabs are intended to hold the latch from inadvertently dislodging, while also (at least theoretically) allowing replacement of the latch if necessary. In practice, removal of the latch from behind the tab can be significantly difficult or can even result in destroying the tab or sidewall/drop door itself. If the tab is broken or weakened by such removal (or otherwise is broken during use of the container), the latch typically can no longer be retained in the sidewall or drop door by the tab. Instead, unless the user decides to throw away the entire sidewall or drop door, the replacement latch must be affixed to the sidewall or drop door by some other means, such as by screws, glue, rivets, or the like. Such “permanent” affixation of the replacement latch not only takes more time than is desirable, but makes any subsequent replacement or maintenance on the latch even more difficult and time-consuming.
Further on that point, and specifically regarding collapsible containers, typical prior art latches are not reversible or otherwise usable for both sidewall latching and drop door latching. Such prior art approaches therefore require a separate latch for drop door latching and sidewall latching as those typically operate (pivot) in opposite directions (the drop door pivots outwardly, but the sidewall pivots inwardly).